This invention relates to a new class of azole derivatives, methods for their use, and processes for their production. The compounds described herein are useful for the treatment of fungal infections in humans and other mammals. The present invention provides a compound represented by the general formula: 
wherein A is the non-hydroxy portion of a triazole antifungal compound of the type containing a secondary or tertiary hydroxy group, n is 0 or 1, m can be 0 to 6; p is 1 or 2; R1, R2, R3 and R4 can each independently be hydrogen, C1-C6 alkyl, hydroxy, OR5, NH2, NR6R7, or halogen; R5, R6 and R7 can each independently be hydrogen, C(O)R8, or C1-C6 alkyl; R8 is C1-C6 alkyl, or a pharmaceutically acceptable salt thereof.
Triazole antifungal compounds are well known in the prior art. Of the several known classes of such compounds, one particularly potent class contains a tertiary hydroxyl group. For example, U.S. Pat. No. 5,648,372 discloses that (2R,3R)-3-[4-(4-cyanophenyl)thiazol-2-yl]-2-(2,4-difluorophenyl)-1-(1H-1,2,4-triazol-1-yl)-butan-2-ol has potent anti-fungal activity. 
The utility of this class of compounds is limited by their low water solubility. Various prior art methods have attempted to address this problem in order to prepare water-soluble forms of these compounds, e.g. for parenteral administration.
WO 97/28169 discloses compounds of the general formula
Rxe2x80x2xe2x80x94OP(O)(OH)2 
wherein Rxe2x80x2 represents the non-hydroxy portion of a triazole antifungal compound of the type containing a tertiary hydroxy group.
EP 829478 discloses compounds of the general formula 
wherein
Q is the remainder of an azole compound of the formula 
possessing antifungal activity;
Z is nitrogen or methine;
R1 and R2 are each independently a hydrogen atom or a group xe2x80x94OY in which Y is a group easily hydrolyzable under physiological condition;
R3 and R4 are each independently a hydrogen or halogen atom, lower alkyl, lower alkoxy, lower alkylthio, (lower alkylcarbonyl)-thiomethyl, carboxy or methoxycarbonyl; and Xxe2x88x92 is a pharmaceutically acceptable anion.
WO 99/15522 discloses compounds of the general formula 
wherein G is H or PO3H2.
WO 98/34934 discloses compounds of the formula 
the N-oxide forms, the pharmaceutically acceptable addition salts and stereochemically isomeric forms thereof, wherein xe2x80x94Axe2x80x94Bxe2x80x94 forms a divalent radical of formula:
xe2x80x94Nxe2x95x90CHxe2x80x94xe2x80x83xe2x80x83(a), 
xe2x80x94CHxe2x95x90Nxe2x80x94xe2x80x83xe2x80x83(b), 
xe2x80x94CHxe2x95x90CHxe2x80x94xe2x80x83xe2x80x83(c), 
wherein one hydrogen atom in the radicals (a) and (b) may be replaced with a C1-6 alkyl-radical and up to two hydrogen atoms in radical (c) may be replaced by a C1-6 alkyl-radical;
L represents the acyl moiety of an amino acid, and thus xe2x80x94Oxe2x80x94L represents an amino acid ester group;
D is a radical of formula 
wherein
X is N or CH;
R1 is halo;
R2 is hydrogen or halo.
U.S. Pat. No. 5,707,977 discloses compounds of the formula 
an acid or base addition salt thereof or a stereochemically isomeric form thereof, wherein A and B taken together form xe2x80x94Nxe2x95x90CHxe2x80x94, xe2x80x94CHxe2x95x90Nxe2x80x94, xe2x80x94CH2xe2x80x94CH2, CHxe2x95x90CHxe2x80x94, xe2x80x94C(xe2x95x90O)xe2x80x94CH2xe2x80x94, xe2x80x94CH2xe2x80x94C(xe2x95x90O); D is a radical of formula 
Alk is a C1-4 alkanediyl radical; R1 is halo; R2 is hydrogen or halo; R3 is hydrogen, C1-6 alkyl, phenyl or halophenyl; R4 is hydrogen, C1-6 alkyl phenyl or halophenyl; R5 is hydrogen or C1-6 alkyl; R6 is hydrogen, C1-6 alkyl, C1-6 alkyloxycarbonyl, or R5 and R6 taken together with the nitrogen atom to which they are attached form a heterocyclic ring.
WO 96/38443 discloses compounds of the formula 
wherein X is independently both F or both Cl or one X is independently F and the other is independently Cl;
R1 is a straight or branched chain (C4-C5) alkyl group substituted by one or two groups convertible in vivo into hydroxy moieties or a pharmaceutically acceptable salt thereof.
WO 98/43970 discloses a quaternized nitrogen-containing imidazol-1-yl or 1,2,4-triazol-1-yl compound wherein one of the nitrogen atoms constituting an azole ring is quaternized with a substituent capable of being eliminated in vivo to be converted into an antifungal azole compound. The preferred compounds have the formula 
(wherein Q is an imidazol-1-yl or 1,2,4-triazol-1-yl group in which one of the nitrogen atoms constituting an azole ring is quaternized with a substituent capable of being eliminated in vivo; Ar is an optionally substituted phenyl group; A is an optionally substituted hydrocarbon group or an optionally substituted heterocyclic group; X1 is an oxygen atom or a methylene group; X2 is an optionally oxidized sulfur atom; m and p respectively represent 0 or 1; Y is an anion; and (1) R3, R4 and R5 may be the same or different and represent a hydrogen atom or a lower alkyl group, or (2) R3 is a hydrogen atom or a lower alkyl group and R4 and R5 are combined with each other to form a lower alkylene group, or (3) R5 is a hydrogen atom or a lower alkyl group and R3 and R4 are combined with each other to form a lower alkylene group) or a salt thereof.
WO 99/33846 discloses compounds of the formula 
wherein R1, R2 and R3 are substituents which comprise the parent secondary or tertiary amine such that one of R1, R2 or R3 may be hydrogen, R4 and R5 are each hydrogen, or an organic or inorganic residue.
U.S. Pat. No. 5,883,097 discloses the water-soluble lactic acid addition salt of the compound represented by the formula 
as suitable for preparation of pharmaceutical formulations for intravenous use.
It has now been found that triazole anti-fungal compounds containing a secondary or tertiary hydroxyl group, including (2R,3R)-3-[4-(4-cyanophenyl)thiazol-2-yl]-2-(2,4-difluorophenyl)-1-(1H-1,2,4-triazol-1-yl)-butan-2-ol, may be converted into prodrugs with superior properties to those previously disclosed by attaching a phosphate containing moiety via a linking group. Specifically, the invention covers compounds of the formula: 
wherein A is the non-hydroxy portion of a triazole antifungal compound of the type containing a secondary or tertiary hydroxy group, n is 0 or 1, m can be 0 to 6; p is 1 or 2; R1, R2, R3 and R4 can each independently be hydrogen, C1-C6 alkyl, hydroxy, OR5, NH2, NR6R7, or halogen; R5, R6 and R7 can each independently be hydrogen, C(O)R8, or C1-C6 alkyl; R8 is C1-C6 alkyl, or a pharmaceutically acceptable salt thereof. The preferred formula I compounds are those where R1, R2, R3 and R4 are each independently hydrogen, C1-C6 alkyl, OR5 or halogen. Most preferred are the formula I compunds where R1, R2, R3 and R4 are each hydrogen.
In a preferred embodiment, A represents the non-hydroxy portion of a triazole antifungal compound of the type containing a tertiary hydroxy group.
The various phosphate containing substituents of formula I may be attached in either an ortho, meta, or para relationship to the ester substituent, with the preferred attachment being either meta or para.
In a preferred embodiment A can be 
wherein R9 represents phenyl substituted by one or more (preferably 1-3) halogen atoms;
R10 represents H or CH3;
R11 represents H, or taken together with R10 may represent xe2x95x90CH2;
R12 represents a 5- or 6 membered nitrogen containing ring which may be optionally substituted by one or more groups selected from halogen, xe2x95x90O, phenyl substituted by one or more groups selected from CN, (C6H4)xe2x80x94OCH2CF2CHF2 and CHxe2x95x90CHxe2x80x94(C6H4)xe2x80x94OCH2CF2CHF2, or phenyl substituted by one or more groups selected from halogen and methylpyrazolyl.
Nitrogen containing heterocycles which R12 may represent include triazolyl, pyrimidinyl, and thiazolyl.
Preferred embodiments comprise:
(1) A compound of formula I where A is a group of formula II and R9 is 2,4-difluorophenyl; or a pharmaceutically acceptable salt thereof;
(2) A compound of (1) above where R10 is methyl and R11 is hydrogen; or a pharmaceutically acceptable salt thereof;
(3) A compound of (2) above where R12 is 4-(4-cyanophenyl)-thiazol-2-yl; or a pharmaceutically acceptable salt thereof;
(4) A compound of (3) above wherein n is 0 or 1, m is 0 or 1, p is 1 and R1, R2, R3 and R4 are each hydrogen; or a pharmaceutically acceptable salt thereof.
Specific examples of A include, but are not limited to, the following: 
In addition to the application of the present invention to structures containing a tertiary alcohol, it should also be understood that this discovery can be applied to anti-fungal agents which contain secondary alcohols. Some examples include, but are not limited to, the following: 
Representative values for m, n, and p are shown below: 
(where A represents the non-hydroxy portion of a triazole anti-fungal compound of the type containing a tertiary or secondary hydroxyl group)
The term xe2x80x9cpharmaceutically acceptable saltxe2x80x9d as used herein is intended to include salts with such counterions as ammonium, alkali metal salts, particularly sodium or potassium, alkaline earth metal salts, particularly calcium or magnesium, and salts with suitable organic bases such as lower alkylamines (methylamine, ethylamine, cyclohexylamine, and the like) or with substituted lower alkylamines (e.g. hydroxyl-substituted alkylamines such as diethanolamine, meglumine (N-methylglucamine), eglumine, triethanolamine or tris(hydroxymethyl)aminomethane). Salts with bases such as piperidine or morpholine are also intended to be encompassed by the term xe2x80x9cpharmaceutically acceptable saltxe2x80x9d.
The term xe2x80x9chalogenxe2x80x9d includes chloro, bromo, fluoro and iodo, and is preferably chloro or fluoro, and most preferably fluoro.
The aliphatic xe2x80x9calkylxe2x80x9d groups may be straight or branched chains having the specified number of carbon atoms, e.g. in the case of C1-C6 alkyl, the alkyl group may have from 1 to 6 carbon atoms.
Preferred embodiments of the present invention, including in each case pharmaceutically acceptable salts thereof are:
(2R,3R)-3-[4-(4-cyanophenyl)thiazol-2-yl]-2-(2,4-difluorophenyl)-1-(1H-1,2,4-triazol-1-yl)-2-[[[o-phosphonooxy]benzoyloxy]-methoxy]butane (compound of example 1)
(2R,3R)-3-[4-(4-cyanophenyl)thiazol-2-yl]-2-(2,4-difluorophenyl)-1-(1H-1,2,4-triazol-1-yl)-2-[[[p-phosphonooxymethyl]benzoyloxy]-methoxy]butane (compound of example 2)
(2R,3R)-3-[4-(4-cyanophenyl)thiazol-2-yl]-2-(2,4-difluorophenyl)-1-(1H-1,2,4-triazol-1-yl)-2-[[[m-phosphonooxymethyl]benzoyloxy]-methoxy]butane (compound of example 3)
(2R,3R)-3-[4-(4-cyanophenyl)thiazol-2-yl]-2-(2,4-difluorophenyl)-1-(1H-1,2,4-triazol-1-yl)-2-[[[[p-phosphonooxymethyl]benzoyloxy]-methoxy]carbonyloxy]butane (compound of example 4)
(2R,3R)-3-[4-(4-cyanophenyl)thiazol-2-yl]-2-(2,4-difluorophenyl)-1-(1H-1,2,4-triazol-1-yl)-2-[[[[m-phosphonooxy]benzoyloxy]methoxy]butane (compound of example 5)
(2R,3R)-3-[4-(4-cyanophenyl)thiazol-2-yl]-2-(2,4-difluorophenyl)-1-(1H-1,2,4-triazol-1-yl)-2-[[[p-phosphonooxy]benzoyloxy]methoxy]butane
(2R,3R)-3-[4-(4-cyanophenyl)thiazol-2-yl]-2-(2,4-difluorophenyl)-1-(1H-1,2,4-triazol-1-yl)-2-[[[o-phosphonooxymethyl]benzoyloxy]methoxy]butane
(2R,3R)-3-[4-(4-cyanophenyl)thiazol-2-yl]-2-(2,4-difluorophenyl)-1-(1H-1,2,4-triazol-1-yl)-2-[[[[o-phosphonooxymethyl]benzoyloxy]methoxy]carbonyloxylbutane
(2R,3R)-3-[4-(4-cyanophenyl)thiazol-2-yl]-2-(2,4-difluorophenyl)-1-(1H-1,2,4-triazol-1-yl)-2-[[[m-phosphonooxymethyl]benzoyloxy]methoxy]carbonyloxy]butane
(2R,3R)-3-[4-(4-cyanophenyl)thiazol-2-yl]-2-(2,4-difluorophenyl)-1-(1H-1,2,4-triazol-1-yl)-2-[[[[m-phosphonooxy]benzoyloxy]methoxy]carbonyloxy]butane (compound of example 6)
(2R,3R)-3-[4-(4-cyanophenyl)thiazol-2-yl]-2-(2,4-difluorophenyl)-1-(1H-1,2,4-triazol-1-yl)-2-[[[[p-phosphonooxy]benzoyloxylmethoxy]carbonyloxy]butane (compound of example 6)
(2R,3R)-3-[4-(4-cyanophenyl)thiazol-2-yl]-2-(2,4-difluorophenyl)-1-(1H-1,2,4-triazol-1-yl)-2-[[[[o-phosphonooxy]benzoyloxy]methoxy]carbonyloxy]butane (compound of example 6)
The aforementioned preferred embodiments of the present invention are listed in the table below.
The compounds of the present invention can be made by conventional methods. Three suitable general procedures are summarized by the following reaction schemes. In these schemes, A represented the non-hydroxy portion of a triazole anti-fungal compound of the type containing a secondary or tertiary hydroxyl group. 
To elaborate on Method 1, the anti-fungal parent compound of interest is converted into ester 2 by reaction with chloride intermediate 1 in the presence of a suitable base, such as potassium hydride. The esterification reaction can be carried out in THF (tetrahydrofuran) or other inert organic solvent and the product may be purified by column chromatography. Chloride 1 can be prepared by the method of Iyer et al. found in Syn. Comm. 25, 2739, (1995) (see xe2x80x9cPreparation of Starting Materialsxe2x80x9d herein, Method 1) or by the alternative method disclosed below in xe2x80x9cPreparation of Starting Materials,xe2x80x9d Method 2. Ester 2 can be subsequently converted into phosphate ester 3 by reaction with a dialkyl phosphate in refluxing acetonitrile. Phosphate ester 3 can be converted to the phosphate acid 4 in one of two ways. If phosphate 4 is the di-tertiary butyl ester, the free phosphate acid can be liberated by treatment with trifluoroacteic acid. Alternatively, if phosphate 4 is the di-benzyl ester, the free phosphate acid can be obtained by hydrogenation in the presence of palladium on carbon in the presence of a suitable solvent. In either case, the final product can be purified via C-18 column chromatography.
To elaborate on Method 2, the anti-fungal parent compound of interest is converted into chloromethylformate 5 by reaction with commercially available chloromethyl chloroformate in the presence of an appropriate base in THF or other solvent at 0xc2x0 C. to 50xc2x0 C. Appropriate bases include potassium hydride and sodium hydride, among others, with the preferred base being potassium hydride. The product 5 may be purified by column chromatography. Chloromethylformate 5 is converted to alcohol 7 by reaction with carboxylate salt 6 in acetonitrile or other appropriate organic solvent. Carboxylate salt 6 can be prepared by the method disclosed in U.S. Pat. No. 4,623,486. Alcohol 7 can be converted to phosphate ester 8 by reaction with a commercially available phosphoramidite in the presence of tetrazole followed by oxidation e.g. by use of hydrogen peroxide or m-chloroperoxybenzoic acid. Ester 8 can be purified by column chromatography. Phosphate ester 8 can then be converted to phosphate acid 9 in one of two ways. If phosphate 8 is the di-tertiary butyl ester, the free phosphate acid can be liberated by treatment with trifluoroacteic acid. Alternatively, if phosphate 8 is the di-benzyl ester, the free phosphate acid can be obtained by hydrogenation in the presence of palladium on carbon in the presence of a suitable solvent. Alternatively, phosphate acid 9 can be prepared from alcohol 7 by reaction with phosphorus oxychloride in an inert organic solvent such as dichloromethane in the presence of an organic base such as pyridine. In either case, the final product can be purified via C-18 column chromatography.
To elaborate on Method 3 the benzyloxybenzoic acids 10 are converted to their respective chloromethyl esters 11 using the procedures described for the preparation of compounds 1 in Method 1. The anti-fungal parent compound of interest is then converted to either its potassium or sodium salt by reaction with either potassium or sodium hydride respectively, in an inert solvent such as THF (tetrahydrofuran), or DMF (N,N-dimethylformamide), or mixtures of both at 0xc2x0 C. to 60xc2x0 C. The chloromethyl esters 11 are then introduced to the reaction mixtures to afford the intermediates 12. The compounds 12 can be purified by column chromatography on silicic acid. The benzyl protecting groups are removed from the compounds 12 by hydrogenation using palladium catalysts in an inert solvent to give the alcohols 13 which can be purified by flash chromatography on silicic acid. The alcohols 13 are coverted to the phosphate esters by reaction with a commercially available phosphoramidite in the presence of tetrazole followed by oxidation e.g. by the use of hydrogen peroxide or m-chloroperoxybenzoic acid. The phosphate esters 14 are converted to their respective phosphate acids 15 by one of the two methods illustrated in Method 2 for the conversion of 8 to 9.
In another aspect then, the present invention provides intermediates of the formula 
wherein A is the non-hydroxy portion of a triazole antifungal compound of the type containing a secondary or tertiary hydroxy group; n is 0 or 1; m is 0 to 6; p is 1 or 2; R1, R2, R3 and R4 can each independently be hydrogen, C1-6 alkyl, hydroxy, OR5, NH2, NR6R7 or halogen; and X is OH or xe2x80x94OL where L is a conventional leaving group such as tosylate, methanesulfonate or triflate; and pharmaceutically acceptable salts thereof.
A preferred embodiment comprises the intermediates of formula III wherein A represents the non-hydroxy portion of a triazole antifungal compound of the type containing a tertiary hydroxy group. Within this preferred embodiment, A is preferably a group of the formula II above. A most preferred embodiment within this subclass comprises compounds where R9 in formula II is 2,4-difluorophenyl. Another most preferred embodiment comprises compounds where R9 is 2,4-difluorophenyl, R10 is methyl and R11 is hydrogen. A still more preferred embodiment of this subclass comprises compounds wherein R9 is 2,4-difluorophenyl, R10 is methyl, R11 is hydrogen and R12 is 4-(4-cyanophenyl)thiazol-2-yl.
A preferred embodiment comprises intermediates of formula III wherein n is 0, p is 1, R1, R2, R3 and R4 are hydrogen, m is 0 or 1, and X is OH.
Another preferred embodiment comprises intermediates of formula III wherein n is 1, p is 1, R1, R2, R3 and R4 are hydrogen, m is 0 or 1 and X is OH.
Another preferred aspect of the present invention comprises the intermediates of the formula 
It will be understood that where the substituent groups used in the above reactions contain certain reaction sensitive functional groups such as amino or carboxylate groups which might result in undesirable side-reactions, such groups may be protected by conventional protecting groups known to those skilled in the art. Suitable protecting groups and methods for their removal are illustrated, for example, in Protective Groups in Organic Synthesis, Theodora W. Greene (John Wiley and Sons, 1991). It is intended that such xe2x80x9cprotectedxe2x80x9d intermediates and end-products are included within the scope of the present disclosure and claims.
The desired end-product of formula I may be recovered in the form of a pharmaceutically acceptable acid salt. As defined previously, the term xe2x80x9cpharmaceutically acceptable saltxe2x80x9d as used herein is intended to include salts with such counterions as ammonium, alkali metal salts, particularly sodium or potassium, alkaline earth metal salts, particularly calcium or magnesium, and salts with suitable organic bases such as lower alkylamines (methylamine, ethylamine, cyclohexylamine, and the like) or with substituted lower alkylamines (e.g. hydroxyl-substituted alkylamines such as diethanolamine, triethanolamine or tris(hydroxymethyl)aminomethane), or with bases such as piperidine or morpholine, and meglumine and eglumine.
It will be appreciated that certain products within the scope of formula I may have substituent groups which can result in formation of optical isomers. It is intended that the present invention include within its scope all such optical isomers as well as epimeric mixtures thereof, i.e. R- or S- or racemic forms.
The pharmaceutically active compounds of this invention may be used alone or formulated as pharmaceutical compositions comprising, in addition to the active triazole ingredient, a pharmaceutically acceptable carrier, adjuvant or diluent. The compounds may be administered by a variety of means, for example, orally, topically or parenterally (intravenous or intramuscular injection). The pharmaceutical compositions may be in solid form such as capsules, tablets, powders, etc. or in liquid form such as solutions, suspensions or emulsions. Compositions for injection may be prepared in unit dose form in ampules or in multidose containers and may contain additives such as suspending, stabilizing and dispersing agents. The compositions may be in ready-to-use form or in powder form for reconstitution at the time of delivery with a suitable vehicle such as sterile water.
Alternatively, the compounds of the present invention can be administered in the form of a suppository or pessary, or they may be applied topically in the form of a lotion, solution, or cream. Additionally, they may be incorporated (at a concentration up to 10%) into an ointment consisting of a white wax or soft, white paraffin base together with the required stabilizers and/or preservatives.
The compounds of the invention are useful because they possess pharmacological activities in animals, including particularly mammals and most particularly, humans. Specifically, the compounds of the present invention are useful for the treatment or prevention of topical fungal infections, including those caused by species of Candida, Tnchophyton, Microsporum, or Epidermophyton. Additionally, they are useful for the treatment of mucosal infections caused by Candida albicans. They can also be used in the treatment of systemic fungal infections caused, for example, by species of Candida albicans, Cryptococcus neoformans, Aspergillus flavus, Aspergillus fumigatus, Coccidioides, Paracoccidiodes, Histoplasma, or Blastomyces.
Thus, according to another aspect of the invention, there is provided a method of treating a fungal infection which comprises administering a therapeutically effective amount of the compound to a host, particularly a mammalian host and most particularly a human patient. The use of the compounds of the present invention as pharmaceuticals and the use of the compounds of the invention in the manufacture of a medicament for the treatment of fungal infections are also provided.
The dosage to be administered depends, to a large extent, on the particular compound being used, the particular composition formulated, the route of administration, the nature and condition of the host and the particular situs and organism being treated. Selection of the particular preferred dosage and route of application, then, is left to the discretion of the physician or veterinarian. In general, however, the compounds may be administered parenterally or orally to mammalian hosts in an amount of from about 5 mg/day to about 1.0 g/day. These doses are exemplary of the average case, and there can be individual instances where higher or lower dosages are merited, and such dosages are within the scope of this invention. Furthermore, administration of the compounds of the present inventions can be conducted in either single or divided doses.
The in vitro evaluation of the antifungal activities of the compounds of the invention can be performed by determining the minimum inhibitory concentration (MIC). The MIC is the concentration of test compound which inhibits the growth of the test microorganism. In practice, a series of agar plates, each having the test compound incorporated at a specific concentration, is inoculated with a fungal strain and each plate is then incubated for 48 h at 37xc2x0 C. The plates are examined for the presence or absence of fungal growth, and the relevant concentration is noted. Microorganisms which can be used in the test include Candida albicans, Asperigillus fumigatus, Trichophyton spp., Microsporum spp., Epidermophyton floccosum, Coccidioides immitis, and Torulopsos gaibrata. It should be recognized that, as prodrugs, some compounds of the invention may not be active in the in vitro test.
The in vivo evaluation of compounds of the present invention can be carried out at a series of dose levels by intraperitoneal or intravenous injection or by oral administration to mice which have been inoculated with a strain of fungus (e.g. Candida albicans). Activity is determined by comparing the survival of the treated group of mice at different dosage levels after the death of an untreated group of mice. The dose level at which the test compound provides 50% protection against the lethal effect of the infection is noted.
The compounds of the present invention substantially increase the solubility of the parent triazole antifungal compound and also release the bioactive parent compound (i.e. function as a prodrug) in human liver S9 experiments.